1. Field of the Invention
The invention relates to an improved apparatus and method for centrifuging and monitoring/controlling the temperature of a liquid, e.g., blood or plasma, within a rotating centrifuge container without degradation of components of the liquid.
2. Description of the Related Art
U.S. Pat. No. 5,603,845, discloses a method and a container for separating a component, such as fibrin monomer, from blood or plasma by centrifugation. Blood is fed to a first annular chamber in the device. The annular chamber is defined by a cylindrical outer wall and a cylindrical inner wall, both walls extending coaxially about a common axis, as well as by a top wall and a bottom wall. The top wall is formed by a piston body displaceable within the first chamber. The method described in U.S. Pat. No. 5,603,845 involves a centrifugation of the device about the common axis to substantially separate blood into a cell fraction and a plasma fraction, followed by the resulting plasma fraction being transferred while influenced by the piston body to a second chamber defined by the outer cylindrical wall. The disclosure of U.S. Pat. No. 5,603,845 is incorporated herein by reference. See, also WO 96/16713, WO 96/16714 and WO 96/16715, the disclosure of which are also incorporated herein by reference.
In U.S. Pat. No. 5,603,845, the outer cylindrical wall extends coaxially with the common axis, whereby a fraction with fibrin monomer is caused to be separated in the second chamber while a suitable enzyme is being added. The separation of fibrin monomer from the plasma fraction in the second chamber is carried out during continued centrifugation whereby a polymerized fibrin is deposited on the cylindrical outer wall of the second chamber, whereafter the fluid fraction collected at the bottom of the second chamber is transferred while influenced by the piston body to the first chamber. The fraction with polymerized fibrin deposited on the cylindrical wall in the second chamber is caused to be dissolved by addition of a solvent and by centrifugation. The dissolved fraction is then transferred to a receiving container placed within the piston rod after enzyme capture and filtration, whereby a fibrin monomer-containing solution is provided.
U.S. Pat. No. 5,603,845 also discloses an apparatus for initialing such a centrifuging. The apparatus includes a housing which is basically divided into three compartments, i.e., an upper compartment, a central compartment, and a lower compartment. The container with the fluid to be separated is placed in the central compartment. Specifically, the container is placed on a rotatable supporting turntable which is rotatably journalled on a journalling shaft, the shaft constituting an output shaft of a motor which is housed in the lower compartment. The motor generates high rotational speed at which the container is rotated about its central axis at a number of process steps. The latter process steps correspond to the separating process which the fluid is to be subjected to whereby it is separated into the desired fluid components. The container is retained on the supporting turntable by a gripper device which engages openings along the lower rim of the container. A motor is arranged in the upper compartment. The motor cooperates with another gripper device which is rotatably journalled and adapted to be vertically displaced so as to engage and cooperate with the piston rod of the container.
EP 592242 describes a novel fibrin sealant method according to which fibrin monomer is prepared and utilized, the fibrin monomer being understood to refer to fibrin I. The monomer can be prepared using apparatus and methods as described in the aforementioned U.S. patent and international publication (U.S. Pat. No. 5,603,845, WO 96/16713, WO 96/16714 and WO 96/16715). Essentially, plasma fibrinogen is subjected to an enzyme which catalyzes the cleavage of fibrinopeptide A and/or B from fibrinogen, i.e., thrombin or a thrombin-like enzyme which converts fibrinogen to fibrin. Nondynamic fibrin monomer compositions can thereafter be obtained by, for example, solubilizing the resulting non-crosslinked fibrin polymer using a low pH, i.e., about pH 4, buffer where the fibrin monomer is prevented from polymerizing until the pH is raised.
WO 98/30304, the disclosure of which is also herein incorporated by reference, discloses a method and centrifuge apparatus of the type described above for separating a component, such as a fibrin monomer, from blood or plasma by centrifugation, to produce, for example, a fibrin sealant. The apparatus is provided with a heat emitting device for controlling the temperature of the blood or plasma and, particularly, for heating the blood or plasma to about 37° C. prior to and during processing with thrombin or thrombin-like enzyme. In preferred embodiments of WO 98/30304, the blood is preheated at relatively low rational speeds while being subjected to a heat source which radiates energy in the visible light range. The temperature of the blood is sensed indirectly using a formula and by measuring the temperature of the air and the temperature of the surface of the blood container. The temperature of the blood determined in this manner is fed to a control unit which controls the heat source.
It has been discovered, however, that heating of the blood or plasma may cause degradation of certain proteins. It would be advantageous to be able to heat the blood or plasma in a process such as disclosed in WO 98/30304, but avoid any concomitant protein degradation.